Millions of acres of American wetlands have been destroyed since the late 1700s, according to the U.S. Fish and Wildlife Service. Early settlers viewed wetlands as disease-ridden swamps that impeded travel and agricultural development. Their solution was to drain the wetlands and turn them into farmable land.
In the mid 1960s, the port was growing in Tacoma. Shipping channels were being expanded, and more land was needed for industrial activities. Like many wetlands in the area, Wapato Creek was diverted into a channelized ditch. Its former path was filled with material removed from the waterways, solving both the need for expanded waterways and more land. The channelized ditch ran along 12th Street East in Fife, then followed Alexander Avenue west to a culvert that feeds into Blair Waterway.
The Lower Wapato Creek site was used at first for staging logs and stockpiling soil from other Port projects. But from the mid 1970s until 2014, it remained an empty field while commercial buildings and homes grew up around it.
Scientists know now that wetlands are not only sources of incredible biodiversity, but they also provide benefits to people, such as flood protection and water filtration. Strict laws protect their existence, and efforts are being made to restore wetlands wherever possible.
Lower Wapato Creek is part of this wetland renaissance. What once was an overgrown field sandwiched between Highway 509 and 12th Street East in Fife is now a hilly stream environment teeming with native plants and wildlife.
In this article we explore how this area morphed from a field into a wetland and how Washington Rock’s materials played a small part.
Solving a 60-Year-Old Problem
Wapato Creek is one of many fish-bearing streams important to the Puyallup Tribe of Indians. It springs up in Edgewood, then meanders through Fife before emptying into Tacoma’s Blair Waterway, a shipping channel connected to Commencement Bay.
Lower Wapato Creek is the last section of the creek. Since the 1960s, it passed under 12th Street in Fife through two culverts, leading to a ditch along the roadway. The culverts, two five-foot-diameter pipes, were elevated above the ditch, making it difficult for fish like salmon to continue their journey upstream to spawn. For juvenile fish, the flow of water through the pipes can be too strong, increasing the risk of injury or death.
Road runoff and litter contaminated the creek. The elevated temperature of the water created an oxygen deficiency, limiting the varieties of fish that could survive in it.
Restoration of Lower Wapato Creek had been on the Port’s radar for years. The goal of restoration was to create an environment better suited to fish and other wildlife that had once thrived in the area. Sites like this, where salmon can transition between freshwater and saltwater, are few in Commencement Bay. The Port of Tacoma worked with the Puyallup Tribe to replace the culverts with a wider bridge, reshape the field into a variety of wetland habitats, and carve a meandering stream channel through the habitat.
As the engineering project manager for the Port of Tacoma, David Myers hired design consultants for the Lower Wapato Creek Habitat project and worked closely with them on design plans. He co-managed project with environmental project manager Mark Rettmann.
Building a functioning wetland habitat required studying the site.
“The Port of Tacoma had a bunch of monitoring wells installed for groundwater monitoring before we started the project,” Myers explained. “We also were monitoring salinity levels at the culverts and also at the inlet.”
This data was fed into modeling software, which predicted where the salt wedge—the area where saltwater and freshwater meet—would end up. This was essential in determining how to slope the streambed and how to shape and plant the surrounding environment.
“The modelling also showed where erosion may be a problem and where we needed different streambed mixes,” Rettmann added.
It also helped to determine the likely types of wetland environments that would emerge in a mixed saltwater-freshwater environment: mud flats, salt marshes, forested uplands, and more.
Permitting, planning, and design work began in January 2020 after years of preparation. Invasive plants like Himalayan blackberry and Scotch broom were removed, and the field was mowed to prepare for excavation.
Constructing the New Habitat
Construction finally began in July 2021.
First, a layer of slag leftover from the ASARCO Smelter era was removed from portions of the site. Once the Department of Ecology gave the green light, the project kicked into gear.
The creek continued to flow through the ditch system while the habitat was constructed within a contained area.
“Think about it like a giant bowl,” Myers explained. A “rim” on both ends of the new habitat separated it from the surrounding environment.
Contractors carved into the field and roughly cut it to shape according to design plans, excavating 180,000 cubic yards of soil. The excavated soil was stockpiled on the north end of the site near existing warehouses. Some of this soil was used to reshape portions of the project while the rest was used as embankment fill material for the SR 167 extension project nearby.
As operators graded the land around the streambed, the streambed itself was constructed.
The project used four different streambed mixes made by Washington Rock, about 4,500 tons of streambed mixes in total. The larger rock mixes were placed in areas where the water moves faster, such as on corners. The larger rock helps to slow erosion along the streambed. Smaller rock mixes were used in straight areas with slower moving water.
Myers stressed the importance of using the correct gradation of material and “washing” them in. The streambed mixes are installed in successive layers, and each layer is sprayed with water. “The finer graded material seals up the mix and prevents water from simply running through it,” Myers said. Without these steps, the stream could flow outside the channel or underneath it, causing the stream surface to run dry and leave fish stranded.
Constructing the streambed correctly will keep the creek on course, limiting erosion that could endanger surrounding developments.
Logs were secured along the banks of the streambed. Each log was chained to 4- to 6-Man Streambed Boulders from Washington Rock, which was buried in the ground to create an anchor. The logs provide shelter for fish and animals and are positioned in a way that directs the flow of the stream away from the shoreline. Holes were drilled in the logs to create pockets for insects, providing a food source for fish when insects are dislodged by waves or weather.
Snags (dead trees) were installed upright throughout the habitat, with branches attached for birds to roost on. Stumps and other woody structures were also installed next to the stream and within the wetlands.
“Over time these structures will rot away, but as the site matures, some trees will die or be blown over and become new snags,” Myers explained.
Rerouting Lower Wapato Creek
Before the creek was ready to inhabit its new path, the culvert was replaced with a full-span bridge in 2022.
The bridge allows fish to easily continue their journey upstream, passing through a 30’ wide tunnel that is better aligned with the height of the creek compared to the old culverts.
Fish biologists scoured the ditch for fish, capturing species like stickleback and sculpin as well as a few flounder, bull trout, and shrimp. These fish were relocated downstream from the project area.
Contractors then began lowering the rims of the project area at both ends while the tide was still high: the upper section near the new bridge and the tail end closest to the Port. As the tide began to recede, contractors worked through the night in a highly coordinated effort. One team pumped water out of the ditch and sealed it off. Simultaneously, other teams continued to lower the rims of the project until the connections from new to old streams were completed.
The next morning, the incoming tide flowed backwards through the meandering stream channel. It slowly reached the same elevation as the freshwater flow in the upstream channel where the final breach was made. Once freshwater and saltwater met, the water began to flow naturally through the new stream channel.
Curating Cultural Artifacts and Native Plants
The Port worked with the Puyallup Tribe of Indians to preserve existing trees and a tree with a hawk’s nest, salvage culturally significant objects unearthed during excavation, and select plants important to the Tribe to re-vegetate the site.
During excavation, the Puyallup Tribe’s Historic Preservation Office identified sixteen culturally significant trees, which were relocated to a culturally appropriate place as directed by the Tribe.
Some of the culturally significant trees are thought to be trees that fell during the last major lahar event on Mount Rainier, circa 1450 CE. It’s theorized that Commencement Bay originally extended back to where I-5 is in present day Fife. The lahar filled the tide flats and pushed the Bay out to its current location, leaving behind the logs buried in mud. Even in the present day, they have the distinct appearance of charring.
Once grading was completed, the soil was amended with large wood chips created by shredding logs found on the site that measured less than 48” in diameter.
“The wood chips will rot over time. It creates a mulch-y soil that’s going to hold moisture and provide nutrients,” Myers said. “The whole idea is to get the plants to put their roots down where the moisture is and keep going deeper. Then hopefully they’ll have a greater survival rate.”
After this layer was compacted, six inches of sandy loam—a natural blend of sand and loam with a minimal amount of silt—were placed on top. The sandy loam was seeded with three different types of native groundcover seeds, which varied by the environment they were placed in. Transitional areas where saltwater and freshwater meet were Areas affected by tidal rise were planted with both freshwater and saltwater species, allowing nature to sort out which species will thrive. The entire site was then covered in jute matting to prevent erosion. Over time, the jute will break down and disintegrate.
Although the Port of Tacoma owns the land the habitat is located on, tribal members still use sites like Lower Wapato Creek for ceremonial purposes. Elderberry, salmonberry, and other berries and conifers were included that tribal members would have gathered historically and still gather in the present day for ceremonial purposes.
Along with a salt marsh seed mix, round 106,700 plugs of emergent bare root plants—plants growing near the stream—were planted in the upper reaches of the salt water wetlands next to the creek. After ground cover was established, an additional 33,000 trees and shrubs were planted by hand. All of the plants selected for the site are native species, such as Douglas fir, spruce, shore pine, thimbleberry, and Nootka rose.
Over time, these plants will dramatically increase in size and drop seeds. As the native plants become more established and the trees canopies expand, the wetland environment will become less habitable for invasive species that thrive in full sun. Other trees such as evergreens will continue to grow under the shade canopy of mature cottonwoods and alders. As the cottonwoods and alders die, they will give way to matures, spruces, and other evergreens.
In 2023, a temporary irrigation system was installed throughout the project site, which will support plant development. Next year it will be removed.
Over the next decade, the Lower Wapato Creek Habitat will be included in the Port’s stewardship program. During this period, Port employees will continue to remove stubborn invasive plants and trash and supplement the native plants as needed. The hope is that this habitat will one day resemble the wetlands of yesteryear.
Present-Day Lower Wapato Creek and Its Future
Standing above the new full-span bridge on 12th Street in Fife, you can just make out the curve of the creek disappearing around a corner. With the tide out, sandpiper-like kildeer skitter along the mudflats searching for food.
Since the creek started running through the new streambed over a year ago, Myers has observed how it has adapted.
“The project was designed to allow nature to move the channel around slightly and make micro adjustments over time,” Myers said.
The creek has moved sediment and created a peninsula. The creek also created small side channels within the streambed. These transformations are good—they mean that the creek is making the habitat its own.
After just a year, the brush is close to impassable. Wildflowers like lupine and gumweed spangle a landscape of thick wild grasses. Thimbleberry, serviceberry, and other shrubs are slowly growing throughout the site. Salt marshes throughout the habitat are growing thick with bulrushes.
The Lower Wapato Creek Habitat provides over 10 additional acres of fish and wetland habitat as well as 8.5 acres of forested upland habitat.
“Our ultimate hope that is shared with the Tribe and others is to see salmon return to Wapato Creek and that it becomes a viable life-supporting waterway again,” Myers said.
Special thanks to Dave Myers with the Port of Tacoma for providing many of the details needed to write this story and to Joe Barrentine of the Port of Tacoma for providing photographs of the project site. Thank you also to Mark Rettmann with the Port of Tacoma, the Port of Tacoma Communications Department, and the Puyallup Tribe of Indians for providing essential feedback.
To learn more about this project, check out the Port of Tacoma project page.